src/runtime/export_test.go      | 14 +++++++++++++-
 src/runtime/malloc.go           | 20 +++++++++++++-------
 src/runtime/mgcscavenge_test.go |  5 ++++-
 src/runtime/mpagealloc_32bit.go | 10 ++--------
 src/runtime/mpagealloc_64bit.go |  6 ++----
 src/runtime/mpagealloc_test.go  |  9 +++++++--
 src/runtime/mpagecache_test.go  |  5 ++++-

diff --git a/src/runtime/export_test.go b/src/runtime/export_test.go
index c8d01fbb1574de6b78faff16ed63b8d8c7362d52..b49bc50f97d594fde94121c027ea5afa38c79f3a 100644
--- a/src/runtime/export_test.go
+++ b/src/runtime/export_test.go
@@ -1066,7 +1066,19 @@ // between the two.
 //
 // This should not be higher than 0x100*pallocChunkBytes to support
 // mips and mipsle, which only have 31-bit address spaces.
-var BaseChunkIdx = ChunkIdx(chunkIndex(((0xc000*pageAlloc64Bit + 0x100*pageAlloc32Bit) * pallocChunkBytes) + arenaBaseOffset*sys.GoosAix))
+var BaseChunkIdx = func() ChunkIdx {
+	var prefix uintptr
+	if pageAlloc64Bit != 0 {
+		prefix = 0xc000
+	} else {
+		prefix = 0x100
+	}
+	baseAddr := prefix * pallocChunkBytes
+	if sys.GoosAix != 0 {
+		baseAddr += arenaBaseOffset
+	}
+	return ChunkIdx(chunkIndex(baseAddr))
+}()
 
 // PageBase returns an address given a chunk index and a page index
 // relative to that chunk.
diff --git a/src/runtime/malloc.go b/src/runtime/malloc.go
index cc22b0f276597e94b5e6138a4fcddb8d5e20bb5b..0341bf2c1c81e622345f18cfcb6b7c0c49f7fa70 100644
--- a/src/runtime/malloc.go
+++ b/src/runtime/malloc.go
@@ -199,15 +199,21 @@ 	// mips32 only has access to the low 2GB of virtual memory, so
 	// we further limit it to 31 bits.
 	//
 	// On ios/arm64, although 64-bit pointers are presumably
-	// available, pointers are truncated to 33 bits. Furthermore,
-	// only the top 4 GiB of the address space are actually available
-	// to the application, but we allow the whole 33 bits anyway for
-	// simplicity.
-	// TODO(mknyszek): Consider limiting it to 32 bits and using
-	// arenaBaseOffset to offset into the top 4 GiB.
+	// available, pointers are truncated to 33 bits in iOS <14.
+	// Furthermore, only the top 4 GiB of the address space are
+	// actually available to the application. In iOS >=14, more
+	// of the address space is available, and the OS can now
+	// provide addresses outside of those 33 bits. Pick 40 bits
+	// as a reasonable balance between address space usage by the
+	// page allocator, and flexibility for what mmap'd regions
+	// we'll accept for the heap. We can't just move to the full
+	// 48 bits because this uses too much address space for older
+	// iOS versions.
+	// TODO(mknyszek): Once iOS <14 is deprecated, promote ios/arm64
+	// to a 48-bit address space like every other arm64 platform.
 	//
 	// WebAssembly currently has a limit of 4GB linear memory.
-	heapAddrBits = (_64bit*(1-sys.GoarchWasm)*(1-sys.GoosIos*sys.GoarchArm64))*48 + (1-_64bit+sys.GoarchWasm)*(32-(sys.GoarchMips+sys.GoarchMipsle)) + 33*sys.GoosIos*sys.GoarchArm64
+	heapAddrBits = (_64bit*(1-sys.GoarchWasm)*(1-sys.GoosIos*sys.GoarchArm64))*48 + (1-_64bit+sys.GoarchWasm)*(32-(sys.GoarchMips+sys.GoarchMipsle)) + 40*sys.GoosIos*sys.GoarchArm64
 
 	// maxAlloc is the maximum size of an allocation. On 64-bit,
 	// it's theoretically possible to allocate 1<<heapAddrBits bytes. On
diff --git a/src/runtime/mgcscavenge_test.go b/src/runtime/mgcscavenge_test.go
index 3b12a2e1e631524e4ea267025214f34966fa42a0..221bff17469368eb8814a49c3c6ba069666150b7 100644
--- a/src/runtime/mgcscavenge_test.go
+++ b/src/runtime/mgcscavenge_test.go
@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"math/rand"
 	. "runtime"
+	"runtime/internal/sys"
 	"testing"
 )
 
@@ -408,7 +409,9 @@ 				BaseChunkIdx + 0xe: {{0, PallocChunkPages}},
 			},
 		},
 	}
-	if PageAlloc64Bit != 0 {
+	// Disable these tests on iOS since we have a small address space.
+	// See #46860.
+	if PageAlloc64Bit != 0 && sys.GoosIos == 0 {
 		tests["ScavAllVeryDiscontiguous"] = setup{
 			beforeAlloc: map[ChunkIdx][]BitRange{
 				BaseChunkIdx:          {},
diff --git a/src/runtime/mpagealloc_32bit.go b/src/runtime/mpagealloc_32bit.go
index fceb4e7a187b7a6d3a0ff060da84ea92a02e8277..41c8239644ef16f5c30b54e1c20bb1a2d8e0aeee 100644
--- a/src/runtime/mpagealloc_32bit.go
+++ b/src/runtime/mpagealloc_32bit.go
@@ -2,19 +2,13 @@ // Copyright 2019 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build 386 || arm || mips || mipsle || wasm || (ios && arm64)
-// +build 386 arm mips mipsle wasm ios,arm64
+//go:build 386 || arm || mips || mipsle || wasm
+// +build 386 arm mips mipsle wasm
 
 // wasm is a treated as a 32-bit architecture for the purposes of the page
 // allocator, even though it has 64-bit pointers. This is because any wasm
 // pointer always has its top 32 bits as zero, so the effective heap address
 // space is only 2^32 bytes in size (see heapAddrBits).
-
-// ios/arm64 is treated as a 32-bit architecture for the purposes of the
-// page allocator, even though it has 64-bit pointers and a 33-bit address
-// space (see heapAddrBits). The 33 bit address space cannot be rounded up
-// to 64 bits because there are too many summary levels to fit in just 33
-// bits.
 
 package runtime
 
diff --git a/src/runtime/mpagealloc_64bit.go b/src/runtime/mpagealloc_64bit.go
index 16577346a7fbe2c30742875f56b4c6b6d4cac0af..8b72c25ffa3ad096026c189ee35489bcae3d1a72 100644
--- a/src/runtime/mpagealloc_64bit.go
+++ b/src/runtime/mpagealloc_64bit.go
@@ -2,10 +2,8 @@ // Copyright 2019 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build amd64 || (!ios && arm64) || mips64 || mips64le || ppc64 || ppc64le || riscv64 || s390x
-// +build amd64 !ios,arm64 mips64 mips64le ppc64 ppc64le riscv64 s390x
-
-// See mpagealloc_32bit.go for why ios/arm64 is excluded here.
+//go:build amd64 || arm64 || mips64 || mips64le || ppc64 || ppc64le || riscv64 || s390x
+// +build amd64 arm64 mips64 mips64le ppc64 ppc64le riscv64 s390x
 
 package runtime
 
diff --git a/src/runtime/mpagealloc_test.go b/src/runtime/mpagealloc_test.go
index 5d979fa95b9ef55a9beabe0404cf1a178d621f6a..857fc140d86d354ed563b0831e44435e90a94dfb 100644
--- a/src/runtime/mpagealloc_test.go
+++ b/src/runtime/mpagealloc_test.go
@@ -7,6 +7,7 @@
 import (
 	"fmt"
 	. "runtime"
+	"runtime/internal/sys"
 	"testing"
 )
 
@@ -165,7 +166,9 @@ 				MakeAddrRange(PageBase(BaseChunkIdx+64, 0), PageBase(BaseChunkIdx+65, 0)),
 			},
 		},
 	}
-	if PageAlloc64Bit != 0 {
+	// Disable these tests on iOS since we have a small address space.
+	// See #46860.
+	if PageAlloc64Bit != 0 && sys.GoosIos == 0 {
 		tests["ExtremelyDiscontiguous"] = test{
 			chunks: []ChunkIdx{
 				BaseChunkIdx,
@@ -571,7 +574,9 @@ 				BaseChunkIdx + 7: {{0, 6}},
 			},
 		},
 	}
-	if PageAlloc64Bit != 0 {
+	// Disable these tests on iOS since we have a small address space.
+	// See #46860.
+	if PageAlloc64Bit != 0 && sys.GoosIos == 0 {
 		const chunkIdxBigJump = 0x100000 // chunk index offset which translates to O(TiB)
 
 		// This test attempts to trigger a bug wherein we look at unmapped summary
diff --git a/src/runtime/mpagecache_test.go b/src/runtime/mpagecache_test.go
index 2ed0c0aa6a0ba82da5c78a1601514120840b5b0b..9cbf0dd7ded2829632544624c43b761a08b36265 100644
--- a/src/runtime/mpagecache_test.go
+++ b/src/runtime/mpagecache_test.go
@@ -7,6 +7,7 @@
 import (
 	"math/rand"
 	. "runtime"
+	"runtime/internal/sys"
 	"testing"
 )
 
@@ -350,7 +351,9 @@ 				BaseChunkIdx: {{0, PallocChunkPages}},
 			},
 		},
 	}
-	if PageAlloc64Bit != 0 {
+	// Disable these tests on iOS since we have a small address space.
+	// See #46860.
+	if PageAlloc64Bit != 0 && sys.GoosIos == 0 {
 		const chunkIdxBigJump = 0x100000 // chunk index offset which translates to O(TiB)
 
 		// This test is similar to the one with the same name for